Latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level

ABSTRACT

Methods, systems, and devices for latency minimization in wireless communications employing multi-level coding and multi-level sequential demodulation and decoding are described. A user equipment (UE) receive a set of codeblock groups in a first time period. Each codeblock group jointly sharing same channel resources may be associated with a respective decoding level of a set of decoding levels. The UE may determine a first outcome for a first codeblock group and a second outcome for a second codeblock group. The UE may then transmit a feedback message that is based on the first outcome and the second outcome. In case that the feedback message indicates that the first outcome or the second outcome is a failed decoding procedure, the UE may receive, in a second time period, a retransmission of all the codeblock groups. These retransmissions may continue on additional time periods until all related codeblock groups are successfully decoded.

FIELD OF TECHNOLOGY

The following relates to wireless communications, including latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level.

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).

Information transmitted between network nodes may be encoded to improve the reliability of the transmitted information. For example, a coding scheme may provide redundancy, which may be used to correct errors that result from the transmission environment. Some wireless communications systems may use multi-level coding and multi-level sequential demodulation and decoding to improve spectral efficiency. A device may employ a hierarchical hybrid automation repeat request (HARQ) procedure that allows for a gradual retransmission of different coding levels that reduces the volume of the retransmitted data. In some cases, hierarchical HARQ procedure related to multi-level coding may lead to an increased overall latency for the corresponding data allocation.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level. Generally, the described techniques provide for latency minimization in systems supporting multi-level coding and multi-level sequential demodulation and decoding). In some cases, a user equipment (UE) may receive a first code block group (CBG) including one or more codeblocks associated with a first decoding level and a second CBG including one or more codeblocks associated with a second decoding level higher than the first decoding level from a base station on the first transmission period. The UE may determine a first outcome of the decoding procedure for a first CBG and a second outcome of the decoding procedure for a second CBG. The UE may then transmit a feedback message based on the first outcome and the second outcome. The feedback message may indicate that at least one of the first outcome or the second outcome is a failed decoding procedure. The UE may then receive retransmissions of all CBGs in a second time period.

A method of wireless communication at a UE is described. The method may include receiving a set of codeblock groups (CBGs) from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, determining a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG, transmitting, to the base station, a feedback message that is based on the first outcome and the second outcome, and receiving, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG, transmit, to the base station, a feedback message that is based on the first outcome and the second outcome, and receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, determining a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG, transmitting, to the base station, a feedback message that is based on the first outcome and the second outcome, and receiving, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG, transmit, to the base station, a feedback message that is based on the first outcome and the second outcome, and receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the first outcome may include operations, features, means, or instructions for determining that the decoding procedure of all codeblocks of the first CBG associated with a first decoding level may be successful, and determining the second outcome may include operations, features, means, or instructions for determining that the decoding procedure of one or more codeblocks of the second CBG associated with a second decoding level may be failed.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the feedback message further may include operations, features, means, or instructions for transmitting an acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for storing log likelihood ratios associated with the one or more failed codeblocks of the second CBG associated with the second decoding level in a corresponding log likelihood ratio buffer, and storing the one or more codeblocks of the first CBG associated with the first decoding level in a decoded codeblocks buffer.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the outcome of the decoding procedure for the first CBG and the outcome of the decoding procedure for the second CBG further may include operations, features, means, or instructions for determining that the decoding procedure of one or more codeblocks of the first CBG associated with a first decoding level may be failed, and deferring the decoding procedure of the one or more corresponding codeblocks of the second CBG associated with a second decoding level.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the feedback message further may include operations, features, means, or instructions for transmitting a negative acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for storing a log likelihood ratios associated with the one or more failed codeblocks of the first CBG associated with the first decoding level in a corresponding log likelihood ratio buffer, and storing post processing samples corresponding to resources occupied by the one or more codeblocks of the second CBG associated with the second decoding level and corresponding to the failed code blocks of the first CBG, where the post processing samples may be stored in a corresponding samples buffer.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for successfully decoding all codeblocks of the first CBG associated with the first decoding level based on receiving the one or more retransmissions of the one or more codeblocks of the first CBG, where the one or more codeblocks include all codeblocks of the first CBG, and decoding all codeblocks of the second CBG associated with the second decoding level based on the successful decoding of all codeblocks of the first CBG associated with multi-level sequential decoding partitioning information for demodulation and decoding of all the corresponding codeblocks of the second CBG.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the base station, a control message responsive to the feedback message, the control message including a retransmission indicator for the first CBG associated with a first decoding level and for the second CBG associated with a second decoding level.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the retransmission indicator includes a hybrid automatic repeat request process identifier and a redundancy version associated with codeblocks of the first CBG and a redundancy version associated with codeblocks of the second CBG.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the control message includes a downlink control information message scheduling jointly shared resources for retransmission of the set of CBGs, including the first CBG and the second CBG.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the UE may be configured to support multi-level coded modulation with a multi-level sequential demodulation and decoding scheme. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first time period includes a first subframe or a first slot, and the second time period includes a second subframe or a second slot.

A method of wireless communication at a base station is described. The method may include transmitting a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, receiving, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG, and transmitting, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

An apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG, and transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

Another apparatus for wireless communication at a base station is described. The apparatus may include means for transmitting a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, receiving, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG, and transmitting, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG, and transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the decoding procedure of all codeblocks of the first CBG associated with a first decoding level may be successful, and determining that the decoding procedure of one or more codeblocks of the second CBG associated with a second decoding level failed.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the feedback message further may include operations, features, means, or instructions for receiving an acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level, where transmitting the retransmission of the set of CBGs includes transmitting the retransmission of the first CBG associated with the first decoding level and the second CBG associated with the second decoding level.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the decoding procedure of one or more codeblocks of the first CBG associated with a first decoding level and the decoding procedure of one or more codeblocks of the second CBG associated with a second decoding level failed.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the feedback message further may include operations, features, means, or instructions for receiving a negative acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the UE, a control message responsive to the feedback message, the control message including a retransmission indicator for the first CBG associated with a first decoding level and for the second CBG associated with a second decoding level.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the retransmission indicator includes a hybrid automatic repeat request process identifier and a redundancy version associated with codeblocks of the first CBG and a redundancy version associated with codeblocks of the second CBG.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the control message includes a downlink control information scheduling jointly shared resources for retransmission of the set of CBGs, including the first CBG and the second CBG.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the base station may be configured to support multi-level coded modulation. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first time period includes a first subframe or a first slot, and the second time period includes a second subframe or a second slot.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communications that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a multi-level coding scheme that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a processing timeline that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a processing timeline that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIGS. 6 and 7 show block diagrams of devices that support latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 8 shows a block diagram of a communications manager that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 9 shows a diagram of a system including a device that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIGS. 10 and 11 show block diagrams of devices that support latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 12 shows a block diagram of a communications manager that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIG. 13 shows a diagram of a system including a device that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

FIGS. 14 through 17 show flowcharts illustrating methods that support latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some wireless communications systems, a network node (e.g., a user equipment (UE), a base station, or another wireless device) may encode a transmission, which may include control information or data, to improve communication reliability. For example, a base station may use a multi-level coding procedure to encode a transmission, and a UE may use a multi-level sequential demodulation and decoding to decode the transmission, which may improve spectral efficiency or link efficiency. In some cases, during the encoding process, the transmission may be divided into one or more codeblock groups (CBGs), each CBG including one or more codeblocks. A plurality of codeblocks from one or more CBGs may be associated with a corresponding codeword. Each codeword may be associated with a decoding level of the multi-level coding and multi-level sequential demodulation and decoding procedure. Correspondingly, each CBG may include codeblocks corresponding to a specific decoding level, such that each CBG is also associated with a specific decoding level. The UE may decode the CBGs, starting with the CBGs associated with the lowest decoding level. However, in some cases, a UE may fail to decode one or more codeblocks associated with a lower coding level (e.g., the one or more codeblocks may fail a cyclic redundancy check (CRC)). Thus, the UE may be unable to decode a higher decoding level due to error propagation (lack of reliable set partitioning information for constellation subsets demodulation/selection), and retransmissions may be done for all the corresponding codeblocks (or CBGs) associated with all the decoding levels. This approach will allow a minimum latency for multi-level coded data transmissions in a case where retransmissions are involved. In some cases, reliable partitioning information would allow successful decoding of CBGs (or corresponding code blocks) associated with a higher decoding levels and their retransmissions. These scenarios may lead to inefficiencies related to excessive retransmissions of codeblocks associated with a higher decoding levels (e.g., lower link efficiency due to retransmissions) in case of hybrid automatic repeat request (HARQ) procedures or automatic repeat request (ARQ) procedures. Hierarchical HARQ approach across decoding levels may be used in communication system with multi-level coding and multi-level sequential demodulation and decoding in order to improve these inefficiencies. In some examples, a drawback of hierarchical HARQ approach is a potential increase in latency because of gradual retransmissions across the decoding levels. Consequently, hierarchical HARQ approach may not be convenient for latency sensitive data.

According to one or more aspects of the present disclosure, a transmitting device (e.g., base station) may transmit multiple CBGs to a receiving device (e.g., a UE). Each codeword may be mapped on multiple CBGs and each codeword may be associated with a different decoding level. More specifically, a first CBG may include a set of codeblocks mapped to a first coding level and a second CBG may include a set of codeblocks mapped to a second coding level. The receiving device (e.g., UE) may receive the transmitted CBGs (including the first CBG mapped to the first decoding level and second CBG mapped to the second decoding level) and may attempt to decode the codeblocks. If the UE determines that at least one codeblock from a corresponding CBG of any of the coding levels has failed to pass the CRC, the UE may send feedback relating to the decoding (depending on an outcome of the decoding procedure of each decoding level). The transmitting device (e.g., base station) may then retransmit all the CBGs associated with the same used channel resources for all the decoding levels irrespective of the transmitted feedback for each one of them specifically (even if only one of the CBGs coupled to the same channel resources failed, all of them will be retransmitted). Such parallel retransmission procedure may reduce latency introduced by sequentially retransmitting codeblocks associated with different decoding levels (e.g., first retransmitting the CBG associated with a first level, followed by the second level, and so on), such a procedure was referred before as hierarchical HARQ.

In a first example, a UE successfully decodes codeblocks included in CBG of a first decoding level (first CBG) and fails to decode codeblocks included in CBG of a second decoding level (second CBG). The UE may then transmit an ACK for the first CBG and a NACK for the second CBG. In a second example, the UE fails to decode codeblocks included in first CBG of the first decoding level and defers to decode codeblocks included in the second CBG of a second decoding level. The UE may then transmit a first NACK for the first CBG and a second NACK for the second CBG. In both cases, the UE receives retransmission of codeblocks included in the first CBG and codeblocks included in the second CBG. The UE continues to receive retransmission of codeblocks included in the first CBG and codeblocks included in the second CBG until all the related codeblocks of both decoding levels are successfully decoded.

Particular aspects of the subject matter described in this disclosure may be implemented to realize one or more of the following potential advantages. The techniques employed by the described UEs may provide benefits and enhancements to the operation of the UEs. For example, operations performed by the UEs may provide improvements to wireless operations. Implementing various aspects of this disclosure may enable usage for hierarchical HARQ since it allows to use a different procedure transparent to a UE in case of latency sensitive data. In particular, one or more aspects of the present disclosure may allow for a hierarchical HARQ procedure for less/non-latency sensitive data where codeblocks/CBGs (or codewords in some cases) are gradually (e.g., hierarchically, in a number of steps) retransmitted following an unsuccessful decoding procedure for one or more levels of the multi-level coded transmission that corresponds to the failed CBGs (or failed codewords). Gradually retransmitting CBGs or codewords in a number of steps may decrease the number of CBGs or codewords that are retransmitted during HARQ procedures. Additionally or alternatively, decreasing the number of retransmitted CBGs or codewords may increase system efficiency and decrease communications overhead in communications systems. In some cases, UEs capable of supporting the hierarchical HARQ procedure may utilize the techniques described herein to potentially improve link efficiency while ensuring reliable communications between UEs and base stations, among other benefits.

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are further described in the context of a coding scheme and processing timelines. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level.

FIG. 1 illustrates an example of a wireless communications system 100 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface). The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105), or indirectly (e.g., via core network 130), or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP)) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be positioned according to a channel raster for discovery by the UEs 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs 115 via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology).

The communication links 125 shown in the wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode).

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless communications system 100 (e.g., the base stations 105, the UEs 115, or both) may have hardware configurations that support communications over a particular carrier bandwidth or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 or UEs 115 that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

One or more numerologies for a carrier may be supported, where a numerology may include a subcarrier spacing (×f) and a cyclic prefix. A carrier may be divided into one or more BWPs having the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some examples, a single BWP for a carrier may be active at a given time and communications for the UE 115 may be restricted to one or more active BWPs.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T_(s)=1/(Δf_(max)·N_(f)) seconds, where Δf_(max) may represent the maximum supported subcarrier spacing, and N_(f) may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period). In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N_(f)) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or others). In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG), the UEs 115 associated with users in a home or office). A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access for different types of devices.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timings, and transmissions from different base stations 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously). In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs)) within a carrier, within a guard-band of a carrier, or outside of a carrier.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions). Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT), mission critical video (MCVideo), or mission critical data (MCData). Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115). In some examples, vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communications, or with both.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC). Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs). Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105).

The wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), also known as the millimeter band. In some examples, the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation).

A base station 105 or a UE 115 may use beam sweeping techniques as part of beam forming operations. For example, a base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions. For example, the base station 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and may report to the base station 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.

In some examples, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station 105 to a UE 115). The UE 115 may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or unprecoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device).

A receiving device (e.g., a UE 115) may try multiple receive configurations (e.g., directional listening) when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions). In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

In some cases, wireless communications system 100 may use a multi-level coding scheme for transmitting a message that may be decoded according to a multi-level sequential demodulation and decoding procedure. For example, a base station 105 may encode a transmission to a UE 115 using a multi-level coding scheme. The UE 115 may receive the encoded transmission and may decode the transmission according to one or more decoding levels of the multi-level coded and modulated transmission. That is, the UE 115 may decode the transmission sequentially from the lowest decoding level to the highest (e.g., according to sequential multi-level demodulation and decoding). In some examples, the UE 115 may decode the transmission according to multi-level coding and parallel independent decoding. In some cases, the UE 115 may depend on the successful demodulation or decoding of the lower levels to decode the higher levels (e.g., there may be a dependency between a higher decoding level and the previous decoding level results). For example, if the UE 115 fails to decode a codeword associated with a first decoding level, the UE 115 may fail to decode a codeword associated with a second decoding level. In some cases, such a decoding level dependency may lead to error propagation of multi-level sequential demodulation and decoding in receivers (e.g., the UE 115), that may result in retransmissions of codewords associated with multiple decoding levels which may cause high signaling overhead (e.g., due to retransmissions) for these cases as well as other inefficiencies in wireless communications system 100.

A hierarchical HARQ used in conjunction with a multi-level sequential demodulation and decoding procedure may account for dependencies between different decoding levels. Hierarchical HARQ may allow to reduce the volume of HARQ related retransmissions. In some cases, a higher decoding level may suffer from increased overall HARQ latency (this will increase ACK latency for the corresponding CBG or transport block). Thus, a hierarchical HARQ allows a wireless device to reduce a volume of HARQ retransmissions. However, a device may suffer from an increased overall latency due to such hierarchical HARQ procedure, and HARQ procedures to reduce or minimize latency for latency sensitive data/devices may be desired.

According to one or more aspects of the present disclosure, a transmitting device (e.g., base station) may transmit multiple CBGs to a receiving device (e.g., a UE). Each codeblock or codeword may be associated with a decoding level of the multi-level coding and multi-level sequential demodulation and decoding procedure. Correspondingly, each CBG may include codeblocks corresponding only to a specific decoding level, such that each CBG is also associated with a specific decoding level. More specifically, a first CBG may include a set of codeblocks associated with a first coding level and a second CBG may include a set of codeblocks associated with a second coding level that is higher than the first decoding level.

The receiving device (e.g., UE 115) may receive the transmitted CBGs coupled through the same channel resources (including the first CBG associated with the first decoding level and second CBG associated with the second decoding level) and may attempt to decode the codeblocks included in the CBGs. If the UE 115 determines that at least one codeblock from the coupled CBGs of any of the coding levels has failed to pass the CRC, the UE 115 may send feedback relating to the decoding (depending on an outcome of the decoding procedure of each decoding level). The transmitting device (e.g., base station) may then retransmit all the CBGs associated with the same used channel resources for all the decoding levels irrespective of the transmitted feedback for each one of them specifically (even if only one of the CBGs coupled to the same channel resources failed, all of them will be retransmitted). Such parallel retransmission procedure may reduce latency introduced by sequentially retransmitting codeblocks associated with different decoding levels (e.g., first retransmitting the CBG associated with a first level, followed by the second level, and so on), such a procedure was referred before as hierarchical HARQ.

In a first example, a UE 115 successfully decodes codeblocks included in CBG of a first decoding level (first CBG) and fails to decode codeblocks included in CBG of a second decoding level (second CBG). The UE may then transmit an ACK for the first CBG and a NACK for the second CBG. In a second example, the UE fails to decode codeblocks included in first CBG of the first decoding level and defers to decode codeblocks included in the second CBG of a second decoding level. The UE may then transmit a first NACK for the first CBG and a second NACK for the second CBG. In both cases, the UE receives retransmission of codeblocks included in the first CBG and codeblocks included in the second CBG. The UE continues to receive retransmission of codeblocks included in the first CBG and codeblocks included in the second CBG until all the related codeblocks of both decoding levels are successfully decoded.

FIG. 2 illustrates an example of a wireless communications system 200 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. In some examples, the wireless communications system 200 may implement aspects of a wireless communications system 100. For example, the wireless communications system 200 may include a base station 105-a with a coverage area 110-a and a UE 115-a, which may be examples of a base station 105 and a UE 115 as described with reference to FIG. 1. The base station 105-a may be associated with a cell which provides wireless communications service within a respective coverage area 110-a. The base station 105-a may transmit information to one or more UEs 115 on a downlink channel 210, and the UE 115-a may transmit messages to the base station 105-a on an uplink channel 215.

The wireless communications system 200 may support a support multi-level coded modulation with a multi-level sequential demodulation and decoding scheme to improve spectral efficiency. In particular. the base station 105-a may implement a multi-level coding procedure to transmit one or more CBGs 205, each CBG including codeblocks associated with a same decoding level, via a downlink channel 210 to UE 115-a. The base station 105-a, the UE 115-a, or both may communicate via the downlink channel 210 or the uplink channel 215. Although a base station 105 is shown for illustrative purpose, the UE 115-a may communicate with various wireless devices, such as another UE 115, a repeater device, or other wireless devices.

In some cases, the wireless communications system 200 may use a multi-level coding scheme for transmitting a message that may be decoded according to a multi-level sequential demodulation and decoding procedure. For example, the base station 105-a may encode a transmission to the UE 115-a using a multi-level coding scheme. In particular, usage of multi-level coded modulation may provide various code protections to various constellation bits that are associated with a subdivision of a constellation divided into smaller subsets. In some examples, the UE 115-a may receive the encoded transmission and may decode the transmission using sequential decoding of one or more decoding levels of the multi-level coding scheme. That is, the UE 115-a may decode the transmission sequentially from the lowest decoding level to the highest decoding level. In an example, the UE 115-a may depend on the successful demodulation or decoding of the lower levels to decode the higher levels (i.e., there may be a dependency between a higher decoding level and the previous decoding level results).

Multi-level coding with multi-level sequential demodulation and decoding on a receiver side may assume strong dependencies of demodulation/decoding of the higher decoding levels on the previous decoding level result (based on whether the previous coding level passed or failed). In some cases, the dependence of higher decoding levels (through set partitioning) on the previous decoding/partitioning level may be high. As described herein, the multi-level coding scheme may use an Ungerboeck set partitioning to partition a modulation constellation into different constellation subsets while partitioning at different levels is protected by different component codes/decoding levels having different code rates to provide a different code protection for different partitioning levels correspondingly. In some examples, Ungerboeck set partitioning may gradually increase a minimum Euclidian distance between constellation points progressively with one or more partitioning steps (and coding levels correspondingly). For instance, the Ungerboeck set partitioning is intended to gradually increase a minimum Euclidian distance between constellation subsets while moving from a low partitioning level to a high partitioning level. Accordingly, the minimum Euclidian distance, and a corresponding code rate, may increase from a lowest coding level (component code) to a highest coding level. A coding level may be decoded using a component code that corresponds to the code rate aligned with the minimum Euclidian distance for the coding level. In some cases, a coding level may be referred to as a decoding level at a UE 115.

In some cases, a UE 115 may not successfully decode one or more higher decoding levels if the previous decoding level fails. In some cases of multi-level coding with Ungerboeck set partitioning, decoding of a decoding level may be dependent on a successful decoding of a previous level. For example, if the UE 115 fails to accurately decode one or more codeblocks of a codeword associated with a first decoding level, the UE 115 may fail to decode one or more corresponding codeblocks of a codeword associated with a second decoding level. In some examples, failing to decode one or more codeblocks of a codeword may include the codeword or codeblocks failing a CRC. In some cases, such a decoding level dependency may lead to error propagation of multilevel sequential decoding in receivers (e.g., the UE 115), that may result in retransmissions of codewords/codeblocks associated with multiple decoding levels which may cause to a lower link efficiency (e.g., due to retransmissions) in these cases as well as other inefficiencies in wireless communications system 200.

As described herein, hierarchical HARQ may be used during a multi-level sequential demodulation and decoding procedure (e.g., a coherent or non-coherent multi-level sequential demodulation and decoding procedure) to account for dependencies between different decoding levels. For example, a UE 115 may receive a transmission encoded according to multi-level coding scheme. The transmission may be divided into one or more CBGs 205, which may include one or more codeblocks associated with the corresponding one or more codewords. In some examples, each CBG 205 may be associated with a decoding level, such that all codeblocks of a given CBG 205 are associated with the same decoding level. The hierarchical HARQ may provide for gradual retransmission of a CBG 205 associated with a lowest failed decoding level.

In some cases, a CBG 205 may be defined to include codeblocks associated with codeword related to a single and the same decoding level. For example, base station 105-a may transmit an encoded transmission 225 to UE 115-a. The encoded transmission 225 may include one or more CBGs 205 (e.g., CBG 205-a and CBG 205-b) on the same channel resource. Although two CBGs 205 are shown in FIG. 2, an encoded transmission 225 may include any number of CBGs 205. In some examples, three or more CBGs 205 (associated with three or more decoding levels, respectively) may be used for a multi-level transmission. In some cases, CBG 205-a may include codeblocks associated with codewords related to the first decoding level while CBG 205-b may include codeblocks associated with codewords from a different (e.g., second) decoding level, which is described in further detail with respect to FIG. 3. In some cases, the time-frequency resources used by codeblocks associated with CBG 205-a and codeblocks associated with CBG 205-b may be the same across decoding levels. For example, the resource elements spanned by codeblocks associated with CBG 205-a and the resource elements spanned by codeblocks associated with CBG 205-b may be the same. Thus, the codeblocks associated with different decoding levels may be coupled together on the same resources (e.g., time-frequency resources), but may be related to different CBGs 205.

In some examples, the UE 115-a may receive encoded transmission 225 and may attempt to decode CBG 205-a, which may be associated with a lower decoding level than CBG 205-b. In one example, the UE 115-a may determine a first outcome of a decoding procedure for a first CBG (CBG 205-a) of a set of CBGs and a second outcome of the decoding procedure for a second CBG (CBG 205-b) of the set of CBGs. The UE 115-a may successfully decode codeblocks from CBG 205-a and may attempt to decode the codeblocks from CBG 205-b. In one example, the UE 115-a may determine that codeblocks of CBG 205-a and codeblocks of CBG 205-b have passed CRC. The UE 115-a may report an acknowledgement (ACK) for CBG 205-a and CBG 205-b to base station 105-a in feedback message 230 via uplink channel 215, so base station 105-a may not retransmit CBG 205-a or CBG 205-b. In some other examples, UE 115-a may successfully decode codeblocks associated with CBG 205-a, but may fail to decode one or more codeblocks associated with CBG 205-b. The UE 115-a may report an ACK for CBG 205-a in feedback message 230 but may report a NACK for CBG 205-b. In order to reduce latency, the base station 105-a may retransmit codeblocks associated with both CBG 205-a and CBG 205-b. Aspects of the present disclosure provide for guaranteed transmission of the known partitioning information (based on the prior successful decoding of the corresponding lower level CBG) for all the retransmissions of the second decoding level CBG. That is, the UE 115-a may not assume new data transmission for the first decoding level until the second decoding level is successfully decoded. For example, an additional redundancy version for codeblocks associated with CBG 205-a and CBG 205-b may be retransmitted until codeblocks of both CBG 205-a and CBG 205-b are successfully decoded at the UE 115-a.

According to one or more aspects described herein, a network scheduler may be aware about data type and its latency sensitivity. In case of latency sensitive data, hierarchical HARQ may be replaced by a more regular HARQ procedures. For instance, a base station 105 may implement HARQ procedures for all the related CBGs coupled (through the same channel resources) to the failed CBG irrespective of their decoding levels and even in case that some of them (associated with the lower decoding levels) has already got a successful decoding from the previous transmission or related to it one or more retransmissions. To minimize latency of HARQ for multi-level coding and multi-level sequential demodulation and decoding, the base station may transmit all redundancy versions (RVs) of all related CBGs coupled to the failed CBGs. In one example where some codeblocks fail from CBG 205-a and from CBG 205-b, the UE 115 may transmit a NACK for CBG 205-a and CBG 205-b. In such a case, the base station 105 may send a following redundancy version for CBG 205-a and also for CBG 205-b (or for all the higher decoding levels coupled to the same range of resource elements). Thus, all the redundancy versions for all the failed CBGs and all the related CBGs coupled to the failed CBGs of different decoding levels are sent at the same time.

In such an example, NACK may be transmitted for CBG 205-a and CBG 205-b from the UE 115-a. The base station 105-a may retransmit redundancy versions for all decoding levels/CBGs (both CBG 205-a and CBG 205-b) at the same time. The UE 115-a may identify retransmission on all decoding levels from the scheduling control message (using lack of “new data indicator” for any decoding level related CBG (CBG 205-a and CBG 205-b in the addressed example)). The UE 115-a may then attempt to decode codeblocks from CBGs associated with the lowest decoding level (CBG 205-a) after HARQ combining. These trials may be continued for every following redundancy version (for CBG 205-a) that is transmitted until the UE 115-a succeeds to pass CRC for the addressed transmission including all associated decoding levels. In some examples, until successful decoding of all lowest level codeblocks (CBG 205-a), the UE 115 may store additional portions of frequency domain (FD) post processing samples associated with every succeeding redundancy version of the failed (or not attempted for decoding) codeblocks of CBG 205-b to be addressed later for decoding once all codeblocks of CBG 205-a pass CRC. Once the codeblocks associated with the lowest decoding level pass CRC (e.g., codeblocks of CBG 205-a), the UE 115-a may demodulate samples for the next decoding level (second decoding level in this example) with the given decoding result from the lowest decoding level (partitioning information) and define log likelihood ratios for all collected redundancy versions of codeblocks associated with CBG 205-b. HARQ combining of all the collected redundancy versions for the higher level codeblocks associated with CBG 205-b may be performed until all relevant failed codeblocks pass CRC.

In another example, where all codeblocks from CBG 205-a pass CRC and one or more codeblocks from CBG 205-b fail CRC, the UE 115 may report ACK for CBG 205-a and NACK for CBG 205-b. In such a case, a transmitter (or base station 105) may send a following redundancy version for all decoding level codeblocks or CBGs coupled to the same resources including CBG 205-a (even though all codeblocks included in CBG 205-a has already passed CRC). By retransmitting all redundancy versions, the base station 105 may increase the likelihood of successful immediate decoding attempt of the CBG 205-b (with known partitioning information from the lowest decoding level or CBG 205-a) for all its following redundancy versions. Thus, further retransmissions of redundancy versions of the lower decoding level even though it already passed CRC may aid in decoding of the higher decoding level in order to avoid a scenario from hierarchical HARQ approach where new first level codeblocks in CBG 205-a coupled to the following redundancy versions of the retransmitted second level codeblocks of CBG 205-b potentially fails and thus postpones a decoding attempt of a following redundancy version for the corresponding CBG 205-b until the partitioning information for CBG 205-b demodulation is available (CRC pass on the corresponding CBG 205-a).

In such an example, next redundancy versions transmission per CBG will be continued for all CBGs associated with the same channel resources or resource elements until all the CBGs pass CRC. In some examples, the UE 115-a may identify retransmissions for all decoding levels/CBGs that are sent at the same time from a scheduling control message (using a lack of “new data indicator” for any of the related CBGs). The UE 115-a may keep the decoded data for all codeblocks of CBG 205-a until all codeblocks from CBG 205-b pass CRC. This decoded data can be used for regeneration on UE side of all the RVs of the codeblocks included in the corresponding CBG 205-a that already passed CRC (there will be no need to decode/demodulate further RVs of CBG 205-a) such that partitioning information for all the further corresponding CBG 205-b retransmissions will be known in advance on UE side to assist the corresponding CBG 205-b retransmissions demodulation. In such an example, partitioning pointers for the second level CBG 205-b demodulation may be available and decoding attempt for every following redundancy version of CBG 205-b can be performed immediately. Thus, the UE 115-a may try to decode codeblocks of CBG 205-b after HARQ combining with subsequent redundancy version retransmissions. The UE 115-a may continue this process for each subsequent redundancy version until all codeblocks of CBG 205-b succeed to pass CRC.

In some cases, performing a hierarchical HARQ procedure may be based on a capability of UE 115-a. For example, performing a hierarchical HARQ procedure may be based on a capability of UE 115-a to store frequency domain samples. This capability may be required in case of latency minimization approach for multi-level coded transmissions with multi-level sequential demodulation and decoding. In some cases, UE 115-a may indicate to base station 105-a whether UE 115-a supports hierarchical HARQ which will allow to a UE to support the proposed approach for latency minimization. UE 115-a may be transparent to a latency minimization approach followed by the base station 105-a.

FIG. 3 illustrates an example of a multi-level coding scheme 300 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. In some examples, the multi-level coding scheme 300 may implement aspects of a wireless communications systems 100 or 200. For example, the multi-level coding scheme 300 may be implemented by a UE 115, a base station 105, or both in combination with hierarchical HARQ (e.g., decoding level based feedback messages) to reduce a volume of the required transmissions.

In some cases, a CBG 305 may include one or more codeblocks 310, each codeblock 310 associated with a codeword. In some cases, the codeword may be associated with a decoding, or coding level, such that each codeword is associated with a decoding level of the multi-level coding and multi-level sequential demodulation and decoding procedure. For example, the first coding level codeword mapping may include CBG 305-a, CBG 305-b, and CBG 305-c associated with a first codeword (CW1) from a first coding level while the second coding level codeword mapping may include CBG 305-d, CBG 305-e, and CBG 305-f associated with a second codeword (CW2) from a second coding level different from the first coding level. In some examples, CBG 305-a, associated with the first codeword from the first coding level, may include codeblock 310-a through codeblock 310-d. CBGs 305-b and CBGs 305-c, also associated with the first codeword from the first coding level, may also include four codeblocks 310. For the second codeword from the second coding level, CBG 305-d may include two codeblocks 310-e and 310-f CBG 305-e and CBG 305-f, also associated with the second codeword from the second coding level, may also each include two codeblocks 310. Although three CBGs 305 are shown per coding level codeword mapping in FIG. 3, any number of CBGs 305 may be included in each coding level codeword mapping.

In some examples, the number of resource elements spanned by codeblocks 310 included in CBG 305-a, CBG 305-b, CBG 305-c, CBG 305-d and associated with CW1 and the corresponding codeblocks 310 included in CBG 305-e, CBG 305-f associated with CW2 may be the same. Correspondingly, in some cases, a number of codeblocks 310 associated with CW1 plus a number of codeblocks 310 associated with CW2 may be coupled together on the same resources, but may be related to different CBGs 305 for HARQ procedures. In some cases, CW1 related codeblocks 310 (i.e., codeblocks associated with the first decoding level) may be shorter in length than CW2 codeblocks 310 (i.e., codeblocks associated with the second decoding level).

In some examples, the difference in codeblocks length may reduce latency when a UE performs multi-level sequential demodulation and decoding.

In some examples, a base station 105 may transmit CBG 305-a during a slot N to a UE 115. The UE 115 may fail to decode one or more of codeblock 310-a through codeblock 310-d during the slot N. In some cases, the UE 115 may fail to decode CBG 305-a due to the failure of the one or more codeblocks 310. The UE 115 may rely on the successful decoding of CBG 305-a to decode CBG 305-d due to the multi-level coding scheme (e.g., error propagation effect). Accordingly, the UE 115 may store samples associated with CBG 305-d to use once CBG 305-a is successfully decoded (e.g., code protected partitioning information that may be used to improve a decoding success rate for higher decoding levels). That is, the UE 115 may pause decoding CBG 305-d after a decoding failure on a previous decoding level, such as for CBG 305-a (e.g., one or more CRC errors for codeblocks 310-a,b,c,d), and may store information/samples related to CBG 305-d. The UE 115 may report a NACK for CBG 305-a and CBG 305-d in a feedback message to the base station 105. In response to receiving the NACK, the base station 105 may retransmit all CW1 codeblocks 310 for CBG 305-a during a later slot (slot N+K).

In some cases, the receiving device may decode codeblock 310-a through codeblock 310-d associated with CW1 successfully after the first retransmission. That is, the UE 115 may decode CBG 305-a without CRC errors during slot N+K. If CBG 305-a is decoded successfully, the UE 115 may decode the retransmission for CBG 305-d transmitted in slot N+K. If the UE 115 successfully decodes CBG 305-a and CBG 305-d, the UE 115 may transmit an ACK message for CBG 305-a and CBG 305-d to the base station 105. If the UE 115 fails to decode CBG 305-a, CBG 305-d, or both again on slot N+K, the UE 115 may transmit a NACK message to the base station 105. In some examples, retransmissions may continue until CBG 305-a and CBG 305-d are successfully decoded or until a maximum number of retransmissions is reached, at which point the process may be restarted. Each retransmission of the first decoding level CBG 305 may arrive with a new redundancy version associated with retransmission of the data on the corresponding second level CBG 305. Various aspects of latency minimization procedures are further described with reference to FIGS. 4-6.

FIG. 4 illustrates an example of a processing timeline 400 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. In some examples, the processing timeline 400 may implement aspects of a wireless communications system 100 or 200 as well as multi-level coding scheme 300. For example, the processing timeline 400 may be implemented by a UE 115 (or receiving device), a base station 105 (or transmitting device), or both to decrease latency. In some examples, the processing timeline 400 may be implemented in combination with hierarchical HARQ (e.g., decoding level based feedback messages).

During a slot N, at 405, a transmitting device may transmit an initial redundancy version (RV0) of a first CBG (e.g., CBG 305-a), which may include codeblocks associated with codeword from a first decoding level (e.g., decoding level 1). At 410, a transmitting device may transmit an initial redundancy version (RV0) of a second CBG (e.g., CBG 305-d), which may include codeblocks associated with codeword of a second decoding level (e.g., decoding level 2). In some examples, each CBG 305 may be associated with a decoding level (e.g., CBG 305-a may be associated with a first decoding level and CBG 305-d may be associated with a second decoding level), such that all codeblocks of a given CBG 305 are associated with the same decoding level. CBG 305-a and CBG 305-d may be examples of CBGs 305 as described with reference to FIG. 3. In some examples, three or more CBGs 305 (associated with three or more decoding levels, respectively) may be used for a multi-level transmission. In some examples, the UE 115 may attempt to decode CBG 305-a and CBG 305-d during slot N. The UE 115 may successfully decode one or more codeblocks associated with the first CBG (e.g., CBG 305-a). The UE 115 may fail to decode one or more codeblocks associated with the second CBG (e.g., CBG 305-d). In such an example, the UE 115 may determine an ACK (e.g., acknowledgement feedback) for the first CBG (e.g., CBG 305-a) and a NACK for the second CBG (e.g., CBG 305-b). The UE 115 may store log likelihood ratios associated with the one or more failed codeblocks of the second CBG (e.g., CBG 305-d) associated with the second decoding level in a corresponding log likelihood ratio buffer. Additionally, the UE 115 may store the decoded codeblocks of the first CBG (e.g., CBG 305-a) in a decoded codeblocks buffer. The UE 115 may utilize the stored decoded codeblocks of the first CBG in order to generate guaranteed partitioning information for the first CBG (e.g., CBG 305-a). As described herein, the UE 115 may transmit a NACK for CBG 305-d from slot N to the transmitting device (e.g., base station 105).

At 415 during slot N+K, the transmitting device (e.g. base station 105) may retransmit a first redundancy version (RV1) associated with a set of codeblocks included in the first CBG (e.g., CBG 305-a) associated with the first decoding level (as CBG 305-a passed CRC at 405). The stored decoded bits of CBG 305-a may be used to regenerate all further RVs of the first decoding level for this CBG to obtain the partitioning information for the second level CBG. At 420, a first redundancy version (RV1) with codeblocks included in the second CBG (e.g., CBG 305-d) associated with the second decoding level. In some cases, the UE 115 may still fail to decode redundancy version 1 (RV1) of the second CBG (e.g., CBG 305-d) after performing HARQ combining. The UE 115 may transmit an ACK (e.g., acknowledgement feedback) for the first CBG (e.g., CBG 305-a) and a NACK for the second CBG (e.g., CBG 305-b). The UE 115 may also store log likelihood ratios associated with the one or more failed codeblocks in slot N+K of the second CBG (e.g., CBG 305-d) associated with the second decoding level in a corresponding log likelihood ratio buffer.

At 425 during slot N+2K, the transmitting device (e.g. base station 105) may retransmit a second redundancy version (RV2) associated with a set of codeblocks included in the first CBG (e.g., CBG 305-a). At 430, the transmitting device (e.g. base station 105) may transmit second redundancy version (RV2) associated with a set of codeblocks included in the second CBG (e.g., 305-d). In some cases, the UE 115 may still fail to decode redundancy version 2 (RV2) of CBG 305-d after performing HARQ combining. Thus, the UE 115 may transmit a NACK for CBG 305-d from slot N+2K and ACK confirmation for CBG 305-a.

At 435 during slot N+3K, the transmitting device (e.g. base station 105) may retransmit a third redundancy version (RV3) of the first CBG (e.g., CBG 305-a). At 440, the transmitting device (e.g. base station 105) may transmit third redundancy version (RV3) of the second CBG (e.g., CBG 305-d). In some cases, the UE 115 may successfully decode redundancy version 3 (RV3) of CBG 305-d after performing HARQ combining. Thus, according to one or more aspects of the present disclosure, the transmitting device (e.g. base station 105) may continue to retransmit codeblocks from a lower and already successfully decoded decoding level until the UE 115 successfully decodes codeblocks from all decoding levels. Retransmissions of decoded codeblocks of a lower decoding level may aid in decoding of the higher decoding level in order to reduce potential latency of hierarchical HARQ approach (e.g., where new first level codeblocks coupled to the following redundancy versions of retransmitted second level codeblocks potentially fails and thus postpones a decoding attempt of a following redundancy version for the corresponding second level codeblocks).

In some instances, all codeblocks associated with the first CBG (e.g., CBG 305-a) on all further redundancy versions (e.g., RV1, RV2 and RV3) may be re-encoded to provide partitioning information for the corresponding codeblocks of the second CBG (e.g., CBG 305-d) along all the retransmissions of CBG 305-d coming after successful decoding of the first CBG (CBG 305-a). In some examples, for slot N+K, slot N+2K, and slot N+3K, the transmitting device (e.g. base station 105) may indicate no new data for any CBG (e.g., CBG 305-a or CBG 305-d) based on a retransmission flag included in a control message.

At 445 during slot N+4K, the transmitting device (e.g. base station 105) may transmit a redundancy version 0 (RV0) of the first CBG (e.g., CBG 305-a) associated with codeword from coding level 1 and carrying a new data. Additionally, at 450 during slot N+4K, the transmitting device (e.g. base station 105) may transmit an RV0 of the second CBG (e.g., CBG 305-d) associated with codeword from coding level 2 and carrying a new data. The UE 115 may successfully decode codeblocks from both the RV0 of the first CBG (e.g., CBG 305-a) and the RV0 of the second CBG (e.g., CBG 305-d). In such cases, the UE 115 may transmit an ACK for CBG 305-a from slot N+4K and an ACK for CBG 305-d from slot N+4K.

FIG. 5 illustrates an example of a processing timeline 500 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. In some examples, the processing timeline 500 may implement aspects of wireless communications system 100 or 200 as well as multi-level coding scheme 300. For example, the processing timeline 400 may be implemented by a UE 115 (or receiving device), a base station 105 (or transmitting device), or both to decrease latency. In some examples, the processing timeline 500 may be implemented in combination with hierarchical HARQ (e.g., decoding level based feedback messages).

During a slot N, at 505, a transmitting device may transmit an initial redundancy version (RV0) of a first CBG (e.g., CBG 305-a), which may include codeblocks associated with codeword from a first decoding level (e.g., decoding level 1). At 510, a transmitting device may transmit an initial redundancy version (RV0) of a second CBG (e.g., CBG 305-d), which may include codeblocks associated with codeword of a second decoding level (e.g., decoding level 2). In some examples, each CBG 305 may be associated with a decoding level (e.g., CBG 305-a may be associated with a first decoding level and CBG 305-d may be associated with a second decoding level), such that all codeblocks of a given CBG 305 are associated with the same decoding level. CBG 305-a and CBG 305-d may be examples of CBGs 305 as described with reference to FIG. 3. In some examples, three or more CBGs 305 (associated with three or more decoding levels, respectively) may be used for a multi-level transmission.

In some examples, the UE 115 may attempt to decode CBG 305-a and CBG 305-d during slot N. The UE 115 may fail to decode one or more codeblocks associated with the first CBG (e.g., CBG 305-a) (e.g., due to one or more codeblocks associated with failing a CRC). The UE 115 may store post processing samples associated with CBG 305-d from slot N, put a decoding procedure for CBG 305-d from slot N on hold. In addition, the UE 115 may store log likelihood ratios associated with the one or more failed codeblocks of the first CBG (e.g., CBG 305-a) associated with the second decoding level in a corresponding log likelihood ratio buffer. The UE 115 may transmit a NACK for CBG 305-a, CBG 305-d, or both from slot N to the transmitting device (e.g., base station 105). The UE 115 may maintain a FD samples buffer for CBG 305-d from slot N.

At 515 during slot N+K, the transmitting device (e.g. base station 105) may transmit a first redundancy version (RV1) associated with a set of codeblocks included in the first CBG (e.g., CBG 305-a) associated with the first decoding level, and, at 520, a first redundancy version (RV1) with codeblocks included in the second CBG (e.g., CBG 305-d) associated with the second decoding level. In some cases, the UE 115 may still fail to decode RV1 of the first CBG (e.g., CBG 305-a) after performing HARQ combining. In such cases, the UE 115 may not attempt or fail a decoding procedure for CBG 305-d. The UE 115 may transmit a NACK for CBG 305-a, CBG 305-d, or both from slot N+K to the transmitting device (e.g., base station 105). The UE 115 may maintain FD samples buffer for CBG 305-d from slot N and slot N+K. In such an example, the UE 115 may maintain two FD samples buffers which may be inferred as being an equivalent to two hierarchical HARQ processes.

At 525 during slot N+2K, the transmitting device (e.g. base station 105) may transmit a second redundancy version (RV2) associated with a set of codeblocks included in the first CBG (e.g., CBG 305-a). At 530, the transmitting device (e.g. base station 105) may transmit second redundancy version (RV2) associated with a set of codeblocks included in the second CBG (e.g., 305-d). In some cases, the UE 115 may still fail to decode redundancy version 2 (RV2) of with the first CBG (e.g., CBG 305-a) after performing HARQ combining. In such cases, the UE 115 may not attempt or fail a decoding procedure for CBG 305-d. The UE 115 may transmit a NACK for CBG 305-a, CBG 305-d, or both from slot N+2K to the transmitting device (e.g., base station 105). The UE 115 may maintain FD samples buffer for CBG 305-d from slot N, slot N+K and slot N+2K. In such an example, the UE 115 may maintain three FD samples buffers which may be inferred as being an equivalent to three hierarchical HARQ processes.

At 535 during slot N+3K, the transmitting device (e.g. base station 105) may transmit a third redundancy version (RV3) of the first CBG (e.g., CBG 305-a). At 540, the transmitting device (e.g. base station 105) may transmit third redundancy version (RV3) of the second CBG (e.g., CBG 305-d). In some cases, the UE 115 may successfully decode redundancy version 3 (RV3) of CBG 305-a after performing HARQ combining.

In addition given the successful decoding of the CBG 305-a after retransmissions, the UE 115 may regenerate all its redundancy versions, including those corresponding to the retransmissions on slots N, N+K, N+2K, N+3K, and may determine code protected partitioning information for the decoding level 2 demodulation and decoding on slots N, N+K, N+2K and N+3K. Then the receiving device may attempt to decode the sets of codeblocks or codewords based on the stored post processing samples corresponding to resources spanned by this set of code blocks from slots N, N+K, N+2K and N+3K. At 545, the UE 115 may successfully decode the codeblocks CBG 305-d using HARQ combining of all or some of redundancy versions for failed codeblocks. The UE 115 may transmit an ACK for CBG 305-a, CBG 305-d, or both from slot N+3K to the transmitting device (e.g., base station 105). In some examples, for slot N+K, slot N+2K, and slot N+3K, the transmitting device (e.g. base station 105) may indicate no new data for any CBG (e.g., CBG 305-a or CBG 305-d) based on a retransmission flag included in a control message.

At 550 during slot N+4K, the transmitting device (e.g., base station 105) may transmit a redundancy version 0 (RV0) of the first CBG (e.g., CBG 305-a) associated with codeword from coding level 1 and carrying a new data. Additionally, at 555 during slot N+4K, the transmitting device (e.g. base station 105) may transmit an RV0 of the second CBG (e.g., CBG 305-d) associated with codeword from coding level 2 and carrying a new data. The UE 115 may successfully decode codeblocks from both the RV0 of the first CBG (e.g., CBG 305-a) and the RV0 of the second CBG (e.g., CBG 305-d). In such cases, the UE 115 may transmit an ACK for CBG 305-a from slot N+4K and an ACK for CBG 305-d from slot N+4K. In some cases, the number of coding levels, the number of slots, or both the UE 115 may keep on hold may be defined in a UE capability report.

FIG. 6 shows a block diagram 600 of a device 605 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of a UE 115 as described herein. The device 605 may include a receiver 610, a communications manager 615, and a transmitter 620. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level, etc.). Information may be passed on to other components of the device 605. The receiver 610 may be an example of aspects of the transceiver 920 described with reference to FIG. 9. The receiver 610 may utilize a single antenna or a set of antennas.

The communications manager 615 may receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The communications manager 615 may determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG. The communications manager 615 may transmit, to the base station, a feedback message that is based on the first outcome and the second outcome, and receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources. The communications manager 615 may be an example of aspects of the communications manager 910 described herein.

The communications manager 615, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 615, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 615, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 615, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 615, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 620 may transmit signals generated by other components of the device 605. In some examples, the transmitter 620 may be collocated with a receiver 610 in a transceiver module. For example, the transmitter 620 may be an example of aspects of the transceiver 920 described with reference to FIG. 9. The transmitter 620 may utilize a single antenna or a set of antennas.

FIG. 7 shows a block diagram 700 of a device 705 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The device 705 may be an example of aspects of a device 605, or a UE 115 as described herein. The device 705 may include a receiver 710, a communications manager 715, and a transmitter 740. The device 705 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level, etc.). Information may be passed on to other components of the device 705. The receiver 710 may be an example of aspects of the transceiver 920 described with reference to FIG. 9. The receiver 710 may utilize a single antenna or a set of antennas.

The communications manager 715 may be an example of aspects of the communications manager 615 as described herein. The communications manager 715 may include a CBG reception component 720, an outcome component 725, a feedback component 730, and a retransmission reception component 735. The communications manager 715 may be an example of aspects of the communications manager 910 described herein.

The CBG reception component 720 may receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The outcome component 725 may determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG.

The feedback component 730 may transmit, to the base station, a feedback message that is based on the first outcome and the second outcome. The retransmission reception component 735 may receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

The transmitter 740 may transmit signals generated by other components of the device 705. In some examples, the transmitter 740 may be collocated with a receiver 710 in a transceiver module. For example, the transmitter 740 may be an example of aspects of the transceiver 920 described with reference to FIG. 9. The transmitter 740 may utilize a single antenna or a set of antennas.

FIG. 8 shows a block diagram 800 of a communications manager 805 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The communications manager 805 may be an example of aspects of a communications manager 615, a communications manager 715, or a communications manager 910 described herein. The communications manager 805 may include a CBG reception component 810, an outcome component 815, a feedback component 820, a retransmission reception component 825, a storage component 830, and a decoding component 835. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The CBG reception component 810 may receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission.

In some cases, the UE is configured to support multi-level coded modulation with a multi-level sequential demodulation and decoding scheme. In some cases, the first time period includes a first subframe or a first slot, and the second time period includes a second subframe or a second slot.

The outcome component 815 may determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG. The feedback component 820 may transmit, to the base station, a feedback message that is based on the first outcome and the second outcome. The retransmission reception component 825 may receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

In some examples, determining the first outcome includes determining that the decoding procedure of all codeblocks of the first CBG associated with a first decoding level is successful. In some examples, determining the second outcome includes determining that the decoding procedure of one or more codeblocks of the second CBG associated with a second decoding level is failed. In some examples, the feedback component 820 may transmit an acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level.

The storage component 830 may store log likelihood ratios associated with the one or more failed codeblocks. For example, storage component 830 may store log likelihood ratios associated with one or more failed codeblocks of the second CBG associated with the second decoding level in a corresponding log likelihood ratio buffer. In some examples, the storage component 830 may store the one or more codeblocks of the first CBG associated with the first decoding level in a decoded codeblocks buffer.

In some examples, the outcome component 815 may determine that the decoding procedure of one or more codeblocks of the first CBG associated with a first decoding level is failed. In some examples, the outcome component 815 may defer the decoding procedure of the one or more corresponding codeblocks of the second CBG associated with a second decoding level.

In some examples, the feedback component 820 may transmit a negative acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level.

In some examples, the storage component 830 may store log likelihood ratios associated with the one or more failed codeblocks of the first CBG associated with the first decoding level in a corresponding log likelihood ratio buffer. In some examples, the storage component 830 may store post processing samples corresponding to resources occupied by the one or more codeblocks of the second CBG associated with the second decoding level and corresponding to the failed code blocks of the first CBG, where the post processing samples are stored in a corresponding samples buffer.

The decoding component 835 may successfully decode all codeblocks of the first CBG associated with the first decoding level based on receiving the one or more retransmissions of the one or more codeblocks of the first CBG, where the one or more codeblocks include all codeblocks of the first CBG. In some examples, the decoding component 835 may decode all codeblocks of the second CBG associated with the second decoding level based on the successful decoding of all codeblocks of the first CBG associated with multi-level sequential decoding partitioning information for demodulation and decoding of all the corresponding codeblocks of the second CBG.

In some examples, the retransmission reception component 825 may receive, from the base station, a control message responsive to the feedback message, the control message including a retransmission indicator for the first CBG associated with a first decoding level and for the second CBG associated with a second decoding level.

In some examples, determining that the retransmission indicator includes a hybrid automatic repeat request process identifier and a redundancy version associated with codeblocks of the first CBG and a redundancy version associated with codeblocks of the second CBG. In some cases, the control message includes a downlink control information message scheduling jointly shared resources for retransmission of the set of CBGs, including the first CBG and the second CBG.

FIG. 9 shows a diagram of a system 900 including a device 905 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The device 905 may be an example of or include the components of device 605, device 705, or a UE 115 as described herein. The device 905 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 910, an I/O controller 915, a transceiver 920, an antenna 925, memory 930, and a processor 940. These components may be in electronic communication via one or more buses (e.g., bus 945).

The communications manager 910 may receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The communications manager 910 may determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG, transmit, to the base station, a feedback message that is based on the first outcome and the second outcome, and receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

The I/O controller 915 may manage input and output signals for the device 905. The I/O controller 915 may also manage peripherals not integrated into the device 905. In some cases, the I/O controller 915 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 915 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, the I/O controller 915 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 915 may be implemented as part of a processor. In some cases, a user may interact with the device 905 via the I/O controller 915 or via hardware components controlled by the I/O controller 915.

The transceiver 920 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 920 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 920 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 925. However, in some cases the device may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 930 may include random-access memory (RAM) and read-only memory (ROM). The memory 930 may store computer-readable, computer-executable code 935 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 930 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 940 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks supporting latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level).

The code 935 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 935 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 935 may not be directly executable by the processor 940 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 10 shows a block diagram 1000 of a device 1005 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The device 1005 may be an example of aspects of a base station 105 as described herein. The device 1005 may include a receiver 1010, a communications manager 1015, and a transmitter 1020. The device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level, etc.). Information may be passed on to other components of the device 1005. The receiver 1010 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The receiver 1010 may utilize a single antenna or a set of antennas.

The communications manager 1015 may transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The communications manager 1015 may receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG. The communications manager 1015 may also transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources. The communications manager 1015 may be an example of aspects of the communications manager 1310 described herein.

The communications manager 1015, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1015, or its sub-components may be executed by a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 1015, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 1015, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 1015, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1020 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1020 may be collocated with a receiver 1010 in a transceiver module. For example, the transmitter 1020 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The transmitter 1020 may utilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a device 1105 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The device 1105 may be an example of aspects of a device 1005, or a base station 105 as described herein. The device 1105 may include a receiver 1110, a communications manager 1115, and a transmitter 1135. The device 1105 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level, etc.). Information may be passed on to other components of the device 1105. The receiver 1110 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The receiver 1110 may utilize a single antenna or a set of antennas.

The communications manager 1115 may be an example of aspects of the communications manager 1015 as described herein. The communications manager 1115 may include a CBG transmission component 1120, a feedback component 1125, and a retransmission component 1130. The communications manager 1115 may be an example of aspects of the communications manager 1310 described herein.

The CBG transmission component 1120 may transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission.

The feedback component 1125 may receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG. The retransmission component 1130 may transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

The transmitter 1135 may transmit signals generated by other components of the device 1105. In some examples, the transmitter 1135 may be collocated with a receiver 1110 in a transceiver module. For example, the transmitter 1135 may be an example of aspects of the transceiver 1320 described with reference to FIG. 13. The transmitter 1135 may utilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a communications manager 1205 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The communications manager 1205 may be an example of aspects of a communications manager 1015, a communications manager 1115, or a communications manager 1310 described herein. The communications manager 1205 may include a CBG transmission component 1210, a feedback component 1215, a retransmission component 1220, and a decoding status determination component 1225. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The CBG transmission component 1210 may transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission.

In some cases, the base station is configured to support multi-level coded modulation. In some cases, the first time period includes a first subframe or a first slot, and the second time period includes a second subframe or a second slot.

The feedback component 1215 may receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG. The retransmission component 1220 may transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

The decoding status determination component 1225 may determine that the decoding procedure of all codeblocks of the first CBG associated with a first decoding level is successful. In some examples, the decoding status determination component 1225 may determine that the decoding procedure of one or more codeblocks of the second CBG associated with a second decoding level failed.

In some examples, the feedback component 1215 may receive an acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level, where transmitting the retransmission of the set of CBGs includes transmitting the retransmission of the first CBG associated with the first decoding level and the second CBG associated with the second decoding level.

In some examples, the decoding status determination component 1225 may determine that the decoding procedure of one or more codeblocks of the first CBG associated with a first decoding level and the decoding procedure of one or more codeblocks of the second CBG associated with a second decoding level failed. In some examples, the feedback component 1215 may receive a negative acknowledgement message for the first CBG associated with the first decoding level and a negative acknowledgement message for the second CBG associated with the second decoding level.

In some examples, the retransmission component 1220 may transmit, to the UE, a control message responsive to the feedback message, the control message including a retransmission indicator for the first CBG associated with a first decoding level and for the second CBG associated with a second decoding level.

In some cases, the retransmission indicator includes a hybrid automatic repeat request process identifier and a redundancy version associated with codeblocks of the first CBG and a redundancy version associated with codeblocks of the second CBG. In some cases, the control message includes a downlink control information scheduling jointly shared resources for retransmission of the set of CBGs, including the first CBG and the second CBG.

FIG. 13 shows a diagram of a system 1300 including a device 1305 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The device 1305 may be an example of or include the components of device 1005, device 1105, or a base station 105 as described herein. The device 1305 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1310, a network communications manager 1315, a transceiver 1320, an antenna 1325, memory 1330, a processor 1340, and an inter-station communications manager 1345. These components may be in electronic communication via one or more buses (e.g., bus 1350).

The communications manager 1310 may transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure, where the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission, receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs, where the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG, and transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources.

The network communications manager 1315 may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager 1315 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1320 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1320 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1320 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. In some cases, the wireless device may include a single antenna 1325. However, in some cases the device may have more than one antenna 1325, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1330 may include RAM, ROM, or a combination thereof. The memory 1330 may store computer-readable code 1335 including instructions that, when executed by a processor (e.g., the processor 1340) cause the device to perform various functions described herein. In some cases, the memory 1330 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1340 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 1340 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1340. The processor 1340 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1330) to cause the device 1305 to perform various functions (e.g., functions or tasks supporting latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level).

The inter-station communications manager 1345 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1345 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1345 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 1335 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1335 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1335 may not be directly executable by the processor 1340 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 14 shows a flowchart illustrating a method 1400 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The operations of method 1400 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1400 may be performed by a communications manager as described with reference to FIGS. 6 through 9. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1405, the UE may receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure. In some cases, the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a CBG reception component as described with reference to FIGS. 6 through 9.

At 1410, the UE may determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs. In some cases, the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by an outcome component as described with reference to FIGS. 6 through 9.

At 1415, the UE may transmit, to the base station, a feedback message that is based on the first outcome and the second outcome. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a feedback component as described with reference to FIGS. 6 through 9.

At 1420, the UE may receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a retransmission reception component as described with reference to FIGS. 6 through 9.

FIG. 15 shows a flowchart illustrating a method 1500 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1500 may be performed by a communications manager as described with reference to FIGS. 6 through 9. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1505, the UE may receive a set of CBGs from a base station in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure. In some cases, the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a CBG reception component as described with reference to FIGS. 6 through 9.

At 1510, the UE may determine a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs. In some cases, the second outcome is based on the first outcome, and the first CBG is associated with a lower decoding level than the second CBG. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by an outcome component as described with reference to FIGS. 6 through 9.

At 1515, the UE may determine that the decoding procedure of one or more codeblocks of the first CBG associated with a first decoding level is failed. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by an outcome component as described with reference to FIGS. 6 through 9.

At 1520, the UE may defer the decoding procedure of the one or more corresponding codeblocks of the second CBG associated with a second decoding level. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by an outcome component as described with reference to FIGS. 6 through 9.

At 1525, the UE may transmit, to the base station, a feedback message that is based on the first outcome and the second outcome. The operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be performed by a feedback component as described with reference to FIGS. 6 through 9.

At 1530, the UE may receive, from the base station in a second time period and based on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources. The operations of 1530 may be performed according to the methods described herein. In some examples, aspects of the operations of 1530 may be performed by a retransmission reception component as described with reference to FIGS. 6 through 9.

FIG. 16 shows a flowchart illustrating a method 1600 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1600 may be performed by a communications manager as described with reference to FIGS. 10 through 13. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1605, the base station may transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure. In some examples, the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed by a CBG transmission component as described with reference to FIGS. 10 through 13.

At 1610, the base station may receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs. In some cases, the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed by a feedback component as described with reference to FIGS. 10 through 13.

At 1615, the base station may transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be performed by a retransmission component as described with reference to FIGS. 10 through 13.

FIG. 17 shows a flowchart illustrating a method 1700 that supports latency minimization for retransmissions in communications systems with multi-level coding and multi-level sequential demodulation and decoding and code block grouping per decoding level in accordance with aspects of the present disclosure. The operations of method 1700 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1700 may be performed by a communications manager as described with reference to FIGS. 10 through 13. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1705, the base station may transmit a set of CBGs to a UE in a first time period, each CBG of the set of CBGs being associated with a respective one decoding level of a set of decoding levels of a multi-level sequential decoding procedure. In some cases, the set of CBGs are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed by a CBG transmission component as described with reference to FIGS. 10 through 13.

At 1710, the base station may receive, from the UE, a feedback message that is based on a first outcome of the decoding procedure for a first CBG of the set of CBGs and a second outcome of the decoding procedure for a second CBG of the set of CBGs. In some cases, the second outcome is based on the first, and the first CBG is associated with a lower decoding level than the second CBG. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed by a feedback component as described with reference to FIGS. 10 through 13.

At 1715, the base station may transmit, to the UE, a control message responsive to the feedback message, the control message including a retransmission indicator for the first CBG associated with a first decoding level and for the second CBG associated with a second decoding level. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be performed by a retransmission component as described with reference to FIGS. 10 through 13.

At 1720, the base station may transmit, to the UE in a second time period and based on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the set of CBGs associated with the corresponding jointly shared channel resources. The operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be performed by a retransmission component as described with reference to FIGS. 10 through 13.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein. 

What is claimed is:
 1. A method for wireless communication at a user equipment (UE), comprising: receiving a plurality of codeblock groups from a base station in a first time period, each codeblock group of the plurality of codeblock groups being associated with a respective one decoding level of a plurality of decoding levels of a multi-level sequential decoding procedure, wherein the plurality of codeblock groups are associated with same jointly shared channel resources occupied by a corresponding portion of a multi-level coded and modulated transmission; determining a first outcome of the decoding procedure for a first codeblock group of the plurality of codeblock groups and a second outcome of the decoding procedure for a second codeblock group of the plurality of codeblock groups, wherein the second outcome for the second codeblock group is based at least in part on the first outcome for the first codeblock group, and the first codeblock group is associated with a lower decoding level than the second codeblock group; transmitting, to the base station, a feedback message that is based at least in part on the first outcome and the second outcome; and receiving, from the base station in a second time period and based at least in part on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the plurality of codeblock groups associated with the corresponding jointly shared channel resources.
 2. The method of claim 1, wherein: determining the first outcome comprises determining that the decoding procedure of all codeblocks of the first codeblock group associated with a first decoding level is successful; and determining the second outcome comprises determining that the decoding procedure of one or more codeblocks of the second codeblock group associated with a second decoding level is failed.
 3. The method of claim 2, wherein transmitting the feedback message further comprises: transmitting an acknowledgement message for the first codeblock group associated with the first decoding level and a negative acknowledgement message for the second codeblock group associated with the second decoding level.
 4. The method of claim 2, further comprising: storing log likelihood ratios associated with the one or more failed codeblocks of the second codeblock group associated with the second decoding level in a corresponding log likelihood ratio buffer; and storing the one or more codeblocks of the first codeblock group associated with the first decoding level in a decoded codeblocks buffer.
 5. The method of claim 1, wherein determining the outcome of the decoding procedure for the first codeblock group and the outcome of the decoding procedure for the second codeblock group further comprises: determining that the decoding procedure of one or more codeblocks of the first codeblock group associated with a first decoding level is failed; and deferring the decoding procedure of one or more corresponding codeblocks of the second codeblock group associated with a second decoding level.
 6. The method of claim 5, wherein transmitting the feedback message further comprises: transmitting a negative acknowledgement message for the first codeblock group associated with the first decoding level and a negative acknowledgement message for the second codeblock group associated with the second decoding level.
 7. The method of claim 5, further comprising: storing log likelihood ratios associated with the one or more failed codeblocks of the first codeblock group associated with the first decoding level in a corresponding log likelihood ratio buffer; and storing post processing samples corresponding to resources occupied by the one or more codeblocks of the second codeblock group associated with the second decoding level and corresponding to the one or more failed codeblocks of the first codeblock group, wherein the post processing samples are stored in a corresponding samples buffer.
 8. The method of claim 5, further comprising: successfully decoding all codeblocks of the first codeblock group associated with the first decoding level based at least in part on receiving one or more retransmissions of the one or more codeblocks of the first codeblock group, wherein the one or more codeblocks comprise all codeblocks of the first codeblock group; and decoding all codeblocks of the second codeblock group associated with the second decoding level based at least in part on the successful decoding of all codeblocks of the first codeblock group associated with multi-level sequential decoding partitioning information for demodulation and decoding of all the corresponding codeblocks of the second codeblock group.
 9. The method of claim 1, further comprising: receiving, from the base station, a control message responsive to the feedback message, the control message comprising a retransmission indicator for the first codeblock group associated with a first decoding level and for the second codeblock group associated with a second decoding level.
 10. The method of claim 9, further comprising: determining that the retransmission indicator comprises a hybrid automatic repeat request process identifier and a redundancy version associated with codeblocks of the first codeblock group and a redundancy version associated with codeblocks of the second codeblock group.
 11. The method of claim 9, wherein the control message comprises a downlink control information message scheduling jointly shared resources for retransmission of the plurality of codeblock groups, including the first codeblock group and the second codeblock group.
 12. The method of claim 1, wherein the UE is configured to support multi-level coded modulation with a multi-level sequential demodulation and decoding scheme.
 13. The method of claim 1, wherein the first time period comprises a first subframe or a first slot, and the second time period comprises a second subframe or a second slot.
 14. A method for wireless communication at a base station, comprising: transmitting a plurality of codeblock groups to a user equipment (UE) in a first time period, each codeblock group of the plurality of codeblock groups being associated with a respective one decoding level of a plurality of decoding levels of a multi-level sequential decoding procedure, wherein the plurality of codeblock groups are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission; receiving, from the UE, a feedback message that is based at least in part on a first outcome of the decoding procedure for a first codeblock group of the plurality of codeblock groups and a second outcome of the decoding procedure for a second codeblock group of the plurality of codeblock groups, wherein the second outcome for the second codeblock group is based at least in part on the first outcome for the first codeblock group, and the first codeblock group is associated with a lower decoding level than the second codeblock group; and transmitting, to the UE in a second time period and based at least in part on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the plurality of codeblock groups associated with the corresponding jointly shared channel resources.
 15. The method of claim 14, further comprising: determining that the decoding procedure of all codeblocks of the first codeblock group associated with a first decoding level is successful; and determining that the decoding procedure of one or more codeblocks of the second codeblock group associated with a second decoding level failed.
 16. The method of claim 15, wherein receiving the feedback message further comprises: receiving an acknowledgement message for the first codeblock group associated with the first decoding level and a negative acknowledgement message for the second codeblock group associated with the second decoding level, wherein transmitting the retransmission of the plurality of codeblock groups comprises transmitting the retransmission of the first codeblock group associated with the first decoding level and the second codeblock group associated with the second decoding level.
 17. The method of claim 14, further comprising: determining that the decoding procedure of one or more codeblocks of the first codeblock group associated with a first decoding level and the decoding procedure of one or more codeblocks of the second codeblock group associated with a second decoding level failed.
 18. The method of claim 17, wherein receiving the feedback message further comprises: receiving a negative acknowledgement message for the first codeblock group associated with the first decoding level and a negative acknowledgement message for the second codeblock group associated with the second decoding level.
 19. The method of claim 14, further comprising: transmitting, to the UE, a control message responsive to the feedback message, the control message comprising a retransmission indicator for the first codeblock group associated with a first decoding level and for the second codeblock group associated with a second decoding level.
 20. The method of claim 19, wherein the retransmission indicator comprises a hybrid automatic repeat request process identifier and a redundancy version associated with codeblocks of the first codeblock group and a redundancy version associated with codeblocks of the second codeblock group.
 21. The method of claim 19, wherein the control message comprises a downlink control information scheduling jointly shared resources for retransmission of the plurality of codeblock groups, including the first codeblock group and the second codeblock group.
 22. The method of claim 14, wherein the base station is configured to support multi-level coded modulation.
 23. The method of claim 14, wherein the first time period comprises a first subframe or a first slot, and the second time period comprises a second subframe or a second slot.
 24. An apparatus for wireless communication at a user equipment (UE), comprising: a processor, memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receive a plurality of codeblock groups from a base station in a first time period, each codeblock group of the plurality of codeblock groups being associated with a respective one decoding level of a plurality of decoding levels of a multi-level sequential decoding procedure, wherein the plurality of codeblock groups are associated with same jointly shared channel resources occupied by a corresponding portion of a multi-level coded and modulated transmission; determine a first outcome of the decoding procedure for a first codeblock group of the plurality of codeblock groups and a second outcome of the decoding procedure for a second codeblock group of the plurality of codeblock groups, wherein the second outcome for the second codeblock group is based at least in part on the first outcome for the first codeblock group, and the first codeblock group is associated with a lower decoding level than the second codeblock group; transmit, to the base station, a feedback message that is based at least in part on the first outcome and the second outcome; and receive, from the base station in a second time period and based at least in part on the transmitted feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the plurality of codeblock groups associated with the corresponding jointly shared channel resources.
 25. The apparatus of claim 24, wherein the instructions are further executable by the processor to cause the apparatus to: determine that the decoding procedure of all codeblocks of the first codeblock group associated with a first decoding level is successful; and determine that the decoding procedure of one or more codeblocks of the second codeblock group associated with a second decoding level is failed.
 26. The apparatus of claim 25, wherein the instructions to transmit the feedback message further are executable by the processor to cause the apparatus to: transmit an acknowledgement message for the first codeblock group associated with the first decoding level and a negative acknowledgement message for the second codeblock group associated with the second decoding level.
 27. The apparatus of claim 25, wherein the instructions are further executable by the processor to cause the apparatus to: store log likelihood ratios associated with the one or more failed codeblocks of the second codeblock group associated with the second decoding level in a corresponding log likelihood ratio buffer; and store the one or more codeblocks of the first codeblock group associated with the first decoding level in a decoded codeblocks buffer.
 28. The apparatus of claim 24, wherein the instructions to determine the outcome of the decoding procedure for the first codeblock group and the outcome of the decoding procedure for the second codeblock group further are executable by the processor to cause the apparatus to: determine that the decoding procedure of one or more codeblocks of the first codeblock group associated with a first decoding level is failed; and defer the decoding procedure of one or more corresponding codeblocks of the second codeblock group associated with a second decoding level.
 29. An apparatus for wireless communication at a base station, comprising: a processor, memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: transmit a plurality of codeblock groups to a user equipment (UE) in a first time period, each codeblock group of the plurality of codeblock groups being associated with a respective one decoding level of a plurality of decoding levels of a multi-level sequential decoding procedure, wherein the plurality of codeblock groups are associated with same jointly shared channel resources occupied by a corresponding portion of multi-level coded and modulated transmission; receive, from the UE, a feedback message that is based at least in part on a first outcome of the decoding procedure for a first codeblock group of the plurality of codeblock groups and a second outcome of the decoding procedure for a second codeblock group of the plurality of codeblock groups, wherein the second outcome for the second codeblock group is based at least in part on the first outcome for the first codeblock group, and the first codeblock group is associated with a lower decoding level than the second codeblock group; and transmit, to the UE in a second time period and based at least in part on the received feedback message indicating that at least one of the first outcome or the second outcome is a failed decoding procedure, a retransmission of the plurality of codeblock groups associated with the corresponding jointly shared channel resources.
 30. The apparatus of claim 29, wherein the instructions are further executable by the processor to cause the apparatus to: determine that the decoding procedure of all codeblocks of the first codeblock group associated with a first decoding level is successful; and determine that the decoding procedure of one or more codeblocks of the second codeblock group associated with a second decoding level failed. 